Metal-inert-gas (MIG) welding is one well known type of welding process. There are a number of different types of power supplies used for MIG welding. Examples of MIG power supplies include phase controlled, pulse width modulated and inverter power supplies. MIG welding is performed using a variety of wire diameters, wire material, and gasses. The wire and gas used depends on the plate or workpiece thickness and material. Wire diameter, wire material, gas and plate thickness are referred to herein as welding conditions.
Most MIG welding machines use at least three parameters to control the welding process. These parameters are: wire feed speed and/or current, voltage, and inductance. Some MIG welding machines also have an inductance control that affects the response of the power source or supply. Typically, a MIG welding machine will have switches and/or knobs on the front panel to select some or all of the operating parameters. The process of setting one or more of these parameters is called herein machine set up.
Some prior art welding machines (as used herein welding machine refers to the power source, controller, wire feeder, and may include a gas source and other ancillary equipment used to effectuate a weld) are capable of controlling the welding arc to optimize the weld. However, proper control requires optimal operating parameters (current and/or wire feed speed and voltage) for the particular welding conditions (wire diameter, wire material and gas mixture used, as well as the plate thickness and joint type that is being welded). Prior art welding machines require the operator to calculate setup parameters (i.e., voltage, current and/or wire feed speed) from tables or equations using the above welding conditions inputs as independent variables. Alternatively, the appropriate settings may be chosen based on past experience, or by trial and error.
If the operator provides erroneous data, or doesn't properly calculate the setup parameters, the result may be poor quality welds or inefficient use of the welding machine or consumables (gas and wire). Thus, the weld quality is dependent upon the operator properly determining setup parameters. It is not unusual for the operators to improperly select the setup parameters and have such poor quality welds that a service call is required.
Accordingly, it would be desirable for a welding machine to automatically sense one or more of the conditions which enter into the decision for setting wire feed speed and/or current and voltage. Moreover, it would be desirable to automatically set one or more of feed speed and/or current or voltage, in response to the sensed condition. Such a welding machine should be capable of utilizing the wide variety of power supplies.